During the regular press briefing, Lu also defended Chinese efforts in curbing North Korea, South Korean news service EDaily reported.

"I would like to point out again China has consistently opposed the misconduct of other countries, or enforcing unilateral sanctions based on their own laws," Lu said.

The U.S. Treasury includes an embargo against Chinese trading companies that the United States says have helped North Korea circumvent existing sanctions.

"These designations include companies that have engaged in trade with North Korea cumulatively worth hundreds of millions of dollars. We are also sanctioning the shipping and transportation companies, and their vessels, that facilitate North Korea's trade and its deceptive maneuvers," Treasury Secretary Steven Mnuchin has said.

China's foreign ministry said it has no issues with implementing international sanctions, and that the sanctions are being actively enforced.

"If Chinese citizens or businesses violate laws in Chinese territory, we will investigate them strictly according to law," Lu said, suggesting the United States may be overstepping its boundaries in seeking out punitive measures against Chinese companies. "If other countries have information on these issues, we can share information and cooperate on pertinent problems."

One individual, 13 entities and 20 vessels were included on the Treasury's blacklist.

One of the Chinese companies under sanctions, Dandong Dongyuan Industrial Co., is suspected of supplying North Korea with equipment and parts related to the development of nuclear bombs and ballistic missiles.

China may be struggling with North Korea and efforts at diplomacy.

Chinese President Xi Jinping's envoy to Pyongyang, Song Tao, met with top North Korean officials Choe Ryong Hae and Ri Su Yong.

Yoo Seung-min, a South Korean opposition party lawmaker, said Wednesday North Korea's snub of China's envoy is a sign Beijing should move in coordination with the United States, including on sanctions, South Korean news service Newsis reported.

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